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HomeMy WebLinkAbout97 - Design Report - Stoneridge PUD - Grading, Drainage GRADING & DRAINAGE PLAN for STONE RIDGE P.U.D. December, 1997 M O R R I S O N ENGINEERS Tr SCIENTISTS 1, SURVEYORS MAIERLE ,INC. SNCE'19t5 Prepared by: An A—P(ayvv-Ot d Company Uv roH�vn H:/2605/011/STORMUT RECEIVED S E P 2 3 1998 GRADING & DRAINAGE PLAN - STONERIDGE P.U.D. INDEX I. An Introduction to the Existing Drainage System II. The Proposed Drainage Plan III. Exhibits APPENDIX A. Existing Stream-Ditch Runoff Calculations B. Existing Stream-Ditch Capacity Calculations C. Existing & Proposed Culvert Calculations D. Proposed DEURET Pond Calculations 1 • \ LD fl _LD Existing Drainage Basins — Stoneridge P.U.D kD 41 `DO �- � n, to ��, -- 1 -- - -`I— •w ! /'`�' 0 p 6 n CANAL Il r 1:- 1- eEDD � I t II LL- 1 " I { /� East Catron Basin 1350 Acres _I •�, • - .�____ , _ • •, •,Of 1 � - _- �-11.. �•,.1•. 1'•�LJu ulf•�r,.y�",•,• • • - _-_ ___-_-- �.J_-__ _1T� -- '/ � __ / .'........ ............ UTH Ik f9TN" -•!AVE Carroll Basin — 415 Acres 4 - -�-` �I I •, ' r -- AVE ------_-� 1 mill ,I � �, 1• ` '�i• Ir- ^t y> �- /1 ' i s 1-sl • I 41! \\\ \ :� O i I' \� �■ �I �•� �II •V6 :3 xl n I; �, .1 p. , rll t �---_, o•' ';�. : � �.I �I ���� � � ��?.: .� � 1 Ili I I � ,Z o �I•. •..�'Ie�: �!• � -�-,� ,��, rA`�:l 1: �•i • ll;��: ` � •'• � t�'„' 11 �' ��� • t p I L 11 Ov—I I � : •a:;r. w --•na -•� V� l / o v , p' I I-- 'rCt� I I I I j -r., '.'01• M � ' .-1 � ! � /� �J � �p• I -���_ YJ I Scale: 111 =20001r-v Jill `' 1 1 �' I. An Introduction to the Existing Drainage System The Stoneridge P.U.D. is comprised of two minor subdivisions and one major subdivision in the city of Bozeman. These subdivisions are located in the east half of Section 2, Township 2 south, Range 5 east. More specifically, Stoneridge is located north of Durston Road, south of Baxter Lane and adjacent the R.O.W. of N. 19'Avenue. The existing drainage system for the land in interest consists of two stream-ditches that flow northerly into the East Gallatin. They are identified as the Carroll stream-ditch and the East Catron stream-ditch Currently,the Carroll stream-ditch is not mapped by the National Flood Insurance Program for the 100 year flood plain. Moreover, the drainage basin is less than twenty-five square miles and therefore, does not require flood hazard evaluation under chapter 16.20 of the Bozeman Area Subdivision Regulations. The Carroll stream-ditch has its point of origination three miles south of Durston Road. Its drainage basin is approximately 415 acres in size and is composed of equal areas of agricultural,residential, and commercial land use. The are numerous manmade features which interrupt flood flows within the natural basin. They include roadways, irrigation ditches, leveled fields, culvert structures, and irrigation diversion structures. Therefore it has been difficult to calculate realistic storm event flows that reach the site. To account for the influences of existing culvert structures and ponding areas upstream of culverts, a longer time of concentration was used to slightly attenuate the peak flows. It is noted that this section of town is fairly mature with few if any retention/detention ponds in place. The Carroll stream-ditch proceeds through town by means of underground concrete piping and open channel stream- ditches. See Exhibit"A",the City of Bozeman Storm Sewer map for the exact path of this stream-ditch.. The rational method and the City of Bozeman Storm Water Master Plan were used to calculate the peak runoff for a given storm event. The summary of runoff flows may be found in the following table: Basin: Carroll stream-ditch Post-Development Flows (CFS) Otitfall Q10 Q25 Q100 Durston Road 70 86 109 W. Oak Street 78 96 123 (The Carroll stream-ditch joins the East Catron stream-ditch just north of W.Oak street.) Table 1 A closer look at the path of the Carroll stream-ditch reveals certain underground structures may be in question. At W. College a 24" CMP conveys about half of the 25 year event with the remaining runoff either backing up into a field or flooding W. College. From here the runoff proceeds by means of a open channel for 1100 feet where a 24" RCP intercepts the flow. Storm inlets in this section of town feed additional runoff to the storm main. The main outfalls from a 31"x50" CMP into Kirk Park where the runoff flows to the north end of the park by means of an open channel. A 36" RCP at the north end of Kirk park appears to be adequate to Stoneridge P.U.D. 2 convey the 25 year storm event further northwest to a stream-ditch. This stream-ditch along the rear lotlines of West Park Manor#3 also appears to have the capacity for the 25 year event with minimal flooding. However, where this stream-ditch meets Durston Road a serious bottle-neck occurs. The 25 year storm event of 86 cfs has to fit into an existing 24" RCP and proceed east along Durston Road. The capacity of the existing 24" RCP is approximately 25-30 cfs. Therefore,what can not fit into the 24" pipe must be conveyed to the east as street flow down Durston Road or it may cross Durston Road and proceed to the east in a swale on the north side of the road. Regardless of the path, the outfall is near the twin 24" CMP crossing in Durston Road near N. 20'Avenue. It is apparent that the storm main in Durston Road is undersized. For details regarding this area see figure 1. 1-3 1.. r rl'\\II .�N. ♦t I, •, 17 O V 0 CY • m —� — .R N UURSTO*IROAD N21C a ,I C I _ - I SIDS 0 - 17 20 i I�— r w' O y ♦n.nay a Figure 1 The Carroll stream-ditch continues to flow north past Durston Road by means of open channel flow. The next obstacle encountered is an existing 36" CMP under Windsor Street. It is surprising to see a corrugated metal pipe under a such a recently constructed road. This culvert is undersized since a headwater depth of 9.6' under outlet control would be required to push the 25 year storm event through. The difference in elevation between the existing stream-ditch bottom and the top of the road is 4.53'. Suggested remedies may include the addition of another 36" CMP or the replacement of the existing CMP with a 31"x5l" ARCP that will pass 93% of the 25 year event and still provide 1.5 feet of cover over the top of pipe. Currently, storm events that can not pass through the existing 36" CMP must overtop the road and flow back into the stream- ditch. Site grading of all lots adjacent to this crossing is imperative to prevent the inundation of building structures. Please see Exhibit "C" for the finished grading contours. As the Carroll stream-ditch continues north it must pass through existing twin 24" RCPs under Maplewood Dr. The capacity of the twin 24" RCPs is approximately 52 cfs under inlet control with a headwater depth of 3.6 feet which is just below the top of road. Unfortunately,the 25 year event produces a runoff of 90 cfs at this location. It is apparent that the twin 24" culverts are not adequate and may require replacement with a 31"x5l" ARCP. The next obstacle the Carroll stream-ditch Stonerid2e P.U.D. 3 encounters is W. Oak Street. Here an existing 31"x5l" ARCP conveys flow under W. Oak Street. The capacity of this culvert is approximately 95 cfs under inlet control with a headwater depth of 5.0 feet. The rational method produced a 25 year storm event rate of 96 cfs. Therefore calculations show that this culvert may barely pass the 25 year peak without overtopping the road. However, considerable ponding will have to occur to achieve this flow. After passing W. Oak Street,the Carroll stream-ditch travels its last 950 feet before joining with the East Catron stream-ditch. Currently, the East Catron stream-ditch is not mapped by the National Flood Insurance Program for the 100 year flood plain. Moreover, the drainage basin is less than twenty-five square miles and therefore, does not require flood hazard evaluation under chapter 16.20 of the Bozeman Area Subdivision Regulations. The East Catron stream-ditch has its point of origination four miles south of Durston Road. Its drainage basin is approximately 1350 acres in size and is composed of equal areas of agricultural, residential, and commercial land use. Once again the numerous manmade features complicates the runoff calculations but not to the degree of the Carroll stream-ditch. The East Catron stream-ditch has fewer obstructions and is conveyed by way of open channel through its entire travel route with the exception of road culverts. Once again the rational method was used to calculate runoff rates with the summary of results found in the following table: Basin: East Catron stream-ditch Post-Development Flows (CFS) Outfall Q 10 Q25 O 100 Durston Road 127 158 197 Tschache Lane 195 241 304 Baxter Lane 198 245 309 Table 2 A closer look at the path of the East Catron stream-ditch reveals that certain underground structures may also be in question, There is an existing 40"x65" CMP under Durston Road with a capacity of 90 cfs operating under outlet control. However,the 25 year storm event produces a peak runoff rate of 158 cfs. Therefore,the culvert appears to be undersized with 60-70 cfs overtopping Durston Road and rejoining the East Catron stream-ditch on the other side. At some time in the future it may be necessary to replace the existing culvert with a 40"x65" ARCP. The East Catron stream ditch proceeds north and eventually meets the Carroll stream-ditch. The joining of these two stream-ditches yields a single stream-ditch that takes the name of the larger stream- East Catron. The next obstacle encountered by the East Catron stream-ditch is Tschache. Lane of the Stoneridge Major Subdivision. Please see Exhibit`B" for street names and locations. At this location the rational method has predicted that the 25 year storm event will produce a runoff rate of 241 cfs. In light of the cost of reinforced concrete arch pipe,two alternatives may be considered. The first alternative is to use a 54"x88" ARCP with a headwater depth of 5.4 feet and a capacity of 240 cfs operating under the inlet control condition. A second alternative may be to use a Tx4' box culvert with a headwater depth of 5.4 feet and a capacity of 240 cfs operating under inlet control. Since the difference in elevation between the culvert invert Stoneridge P.U.D. 4 and the centerline elevation of Tschache Lane is six feet,water will not overtop the road with either alternative. It is noted that as the size of these concrete culverts become extraordinarily large so does the cost. It may be advantageous to look at a third alternative using corrugate metal pipe as a cost effective solution. The Stoneridge P.U.D. offers one last obstruction to the East Catron stream-ditch. Baxter Lane has an existing 45"x73" CMP with a capacity of 150 cfs under the outlet control condition. The rational method has predicted that the 25 year storm event will produce a runoff rate of 245 cfs. Since this culvert can not pass the entire flow, a pond forms to the south of Baxter Lane and extends easterly to the barrow ditch of N. 191h Avenue. At this location there is an existing 36"x58" ARCP that crosses N. 19`h Avenue and some of this backup flow passes through this culvert to the east side of N. 19t'Avenue where a second pond is formed. These make-shift pond areas will be filled in during construction of the Stoneridge Subdivision which may amplify flooding issues for properties near the intersection of the stream-ditch and Baxter Lane. Grading in this area can be implemented such that the overflow runoff at Baxter Lane can safely pass over the road surface and back into the East Catron stream-ditch without inundating buildings. An additional solution may be to replace the existing undersized culvert at Baxter Lane with a new culvert possessing adequate capacity. This would allow the 25 year event to be passed through the culvert. However, a larger storm event would still cause possible flooding if special site grading is not performed. Therefore, site grading is probably one of the most cost effective ways to remedy the drainage problem at Baxter Lane. Stoneridge P.U.D. 5 III. Proposed Drainage Plan The Stoneridge P.U.D. Drainage Plan consist of two drainage systems. The primary system is designed to provide public convenience and to accommodate relatively moderate frequent flows. The major drainage system has a much greater capacity to convey more water and operates when the rate or volume of runoff exceeds the capacity of the minor system. The return period for the minor drainage system shall be 25 years. Larger return periods shall be conveyed through the major drainage system. Development tends to increase downstream peak flow by increasing runoff volumes and by decreasing the time it takes the runoff to travel downstream. As part of the minor drainage system, retention and detention ponds designed for the 10 year return period shall be implemented to reduce the downstream impact to levels that existed before the Subdivision was created. The ponds will also provide settlement time for sediment and other storm water pollutant loads to drop out. Design of the Stoneridge P.U.D. Grading and Drainage Plan will take advantage of the natural features that will contribute to the management of storm water. Engineering techniques shall be used to preserve and enhance the natural features and processes of the site. This in turn will maximize post-development economic and environmental benefits, particularly in combination with open space and recreational uses. Our design shall improve the effectiveness of the natural systems, rather than negate, replace or ignore them. The Major Drainage System: The backbone of the major drainage system is comprised of the Carroll and East Catron stream-ditches. These waterways shall have the channel capacity to convey the runoff generated by return periods equal to or less than 100 years without inundating any building structures. However, all culverts placed within these waterways shall be designed for the 25 year return period. Specifying culverts for an event greater than the 25 year return period would result in excessive culvert costs with a minimal reduction in the potential for adverse consequences. A smaller portion of the society's funds may be more wisely invested in site grading and specifying floor elevations for lots adjacent to these waterways to accomplish the same goal. Site grading shall be completed so that storm events greater than the 25 year return period will pass over roadways or through emergency overflow areas without inundating any building structures or causing significant erosion. This is imperative due to the high property values associated with commercial development. Another element of the major drainage system is the N. 19`" Greenway Swale. This is a manmade meandering shallow swale that parallels N. 19" and is located within the 50' Public Greenway Corridor. It will contribute to the aesthetic beauty of this community and its drainage purpose will hardly be noticeable when it's not raining. The shallow swale shall be designed to convey the 100 storm event with culverts under roads being designed for the 25 year return period. Site grading shall be completed so that storm events greater than the 25 year return period will pass over roadways or through emergency overflow areas without inundating any building structures or causing significant erosion. Stoneridge P.U.D. 6 A summary of results are as follows: Post Q100 Min.Bottom Width Side Slopes Depth Top Swales and Natural Channels (CFs) (Ft) (11-V) (Ft) (FI) Carroll stream-ditch 152* 8 4:1 2.0 24 East Catron stream-ditch 381* 23.6 4:1 2.0 40 West N. 19'Greenway Swale Durston to W.Stevens 14.4 10 3:1 .48 13 W.Stevens to W.Oak 22.0 10 3:1 .60 14 W.Oak to Tschache Ln. 33.0 10 3:1 .76 15 Tschache Ln to Baxter Ln. 42.0 10 3:1 .87 16 East N. 19'Greenway Swale Tschache Ln to Baxter Ln. 9.5 10 3:1 .40 13 Swale along east boundary of Stoneridge Minor#2 19.3 10 3:1 .60 14 Note:All waterways have a bedslope of.8%or greater and are assumed to be grass lined with some brush(n=.032) * 100 year event calculated assuming entire drainage basin is developed. Culverts Carroll stream-ditch @ Charolet St. New 31"x51"ARCP @ N.22nd New 31"x51"ARCP @ Windsor May replace exist.36"CMP w/31"x51"ARCP @ Maplewood May replace exist.Twin 24"RCP w/31"x51"ARCP @ W.Oak Existing 31"x51"ARCP East Catron stream-ditch @ Tschache Ln New 54"x88"ARCP or 4'x7'box section @ Baxter Ln May replace exist.45"x73"CMP w/54"x88"ARCP or 4'x7'box section West N. 19'Greenway Swale @ N.22"d New 15"RCP @ W.Stevens New 18"RCP @ W.Oak New 24"RCP @ Tschache Ln New 27"RCP @"J"Drive Replace exist 24"CMP w/27"RCP East N. 19'Greenway Swale @"H"Drive New 15"x26"ARCP(may have cover problems) South R.O.W.Baxter Ln. @"H"Drive New 12"RCP Note:All culverts are sized to pass the 25 year return period. Stoneridge P.U.D. 7 The Minor Drainage System: The minor drainage system is comprised of streets, curb chases, swales, and detention/retention ponds. All runoff from lots that are adjacent to the east boundary of the plat shall drain to the N. 19'h Greenway Swale. The N. 19`h Greenway Swale conveys runoff from approximately one-third of the entire Stoneridge P.U.D. to the 81,750 cft detention pond located near the intersection of the East Catron stream-ditch and Baxter Lane. Please see Exhibit`B" for Community Pond locations. This detention pond is designed to contain the 10 year storm event while releasing flow into the East Catron stream-ditch through an outlet structure. The outlet structure is a 15" RCP laid flat that has a release rate that is equal to or less than the 10 year pre- development runoff rate. If larger storm events are encountered the emergency overflow, rip- rapped, broad crested weir will provide a designated path for the overflow to pass into the East Catron stream-ditch with negligible erosion to the pond or stream banks. Likewise, lots that are adjacent to the west boundary of the plat shall also drain away from their respective street frontage to the rear lotlines. These lots shall have on-site detention ponds to prevent runoff from flowing directly into the East Catron. The detention ponds shall be designed to contain the 10 year storm event with the outlet structure releasing into the major waterway at a rate that is equal to or less than the 10 year pre-development rate. If larger storm events are encountered the pond's emergency overflow broad crested weir will provide a designated path for the overflow to pass into the East Catron stream-ditch with negligible erosion to the pond or stream banks. The Stoneridge Minor Subdivision#2, a portion of the Stoneridge P.U.D. that is located between Tschache Ln. And Baxter Ln. and east of N. 19'h Avenue, is divided into two drainage basins. The runoff from the east drainage basin shall collect and flow in a shallow swale down the east boundary of Stoneridge Minor Subdivision#2. The runoff passes under"H"Drive through a 15"x26" ARCP where it outfalls into a 7200 cft holding basin."The runoff from the west drainage basin shall collect and flow down the east barrow ditch of N. 191h Avenue outfalling into the same 7200 cft holding basin. This holding basin is connected to the previously mentioned 81,750 cft detention pond(located on the west side of N. 19`h Avenue near the intersection of the East Catron stream-ditch and Baxter Ln.)by means of an existing 36"x54" ARCP under N. 19'h Avenue. The design of the 81,750 cft detention pond included the entire contributing area from the Stoneridge Minor Subdivision#2. The holding basin bottom elevation is the same as the invert elevation of the 36"x54" ARCP on the west side of N. 19'h Avenue so that no standing water in the basin will result. When storms larger than the 10 year event are experienced the holding basin will overflow across Baxter Ln. into the east barrow ditch of N. 19"Avenue just west of Anderson Precast Concrete f The Wetland Park Area located near lot 45 shall have minimal site grading performed as to reduce the impact to existing wetland flows and stream-ditch overflow patterns. This area shall remain a natural aesthetic benefit to the community and environment. A combination of lot grading and street elevations shall prevent building inundation and provide for emergency overflow relief. It is noted that all lots within the Stoneridge P.U.D. shall not contribute significant runoff to their respective frontage streets. The flow carried within the street shall be from rainfall that actually lands on the street itself. This runoff shall be diverted from street surfaces at Stoneridge P.U.D. 8 intersections or sump locations through curb chases into detention pond facilities designed to the aforementioned criteria. For locations of all community detention/retention ponds,please see Exhibit`B". The summary of results are as follows: Communitv Ponds Description Pond Volume Outlet Structure Depth Release Rate (cft) (Ft) (cfs) Pond#1 81,750 15"RCP @ 015'. 3.2 10.6 Pond#2 1,730 Retention 1.0 NA Pond#3 1,790 6"HDPE @ 0% .58 0.58 Pond#4 1,445 6"HDPE @ 0% .48 0.65 Pond#5 1,200 8"HDPE @ 0% .60 1.20 Pond#6 1,175 6"HDPE @ 0% .59 .73 Pond#7 1,400 4"PVC @ 0% 1.39 .50 Pond#8 2,475 6"HDPE @ 0% 1.65 1.22. Pond#9 870 6"HDPE @ 0% .43 .58 Pond#10 3,368 8"HDPE @ 0% 1.68 2.2 The individual on-site detention ponds shall be designed for each lot that is adjacent to the west boundary of the plat. Since this task requires building and parking lot layouts specific to each lot, a representative lot shall be used to illustrate the feasibility of this concept. Moreover, if a retention pond can be shown to work then a detention pond shall present no problem since detention ponds require less volume than retention ponds. Please see the following calculations. Lot= 1.0 acre Impervious Area= .55 acres @ C = .95 Grassed Area= .45 acres n, C = .15 Total= 1.0 @ C = .68 10 year 2Hr storm event, I = .41 in/hr Qp= CIA=(.68)*(.41 in/hr)*(1.0 acres) _ .28 cfs Vol Hyd= Qp*Dur= .28*2hr*3600 sec/hr=2016 cft Assume .5 ft deep pond, Therefore,Area= 2016 cft/.5ft=4032 sft or(4032 sft/43560 sft/acre)*100 = 9.26% of a lot. Conclusion: Impervious Area = 55.00% Grassed Area = 35.74% Grassed Ret. Pond = 9.26% (or less than 21%of the grassed area shall be reserved for a pond) It is further noted that all runoff generated from the 10 year storm event upon the Stoneridge P.U.D. will be intercepted by a detention or retention pond before it is allowed to flow into a natural stream-ditch. Stoneridge P.U.D. 9 The Storm Water Maintenance Plan: The maintenance of the onsite stormwater collection, detention and discharge release appurtenances shall be integrated as part of the duties of maintenance personnel responsible for normal grounds keeping. Duties shall include routine inspections to ensure that debris,yard waste, and seasonal ice does not impede operation of the detention ponds, and discharge structures. These inspections shall occur after each major runoff event and on a continued monthly basis throughout the year. All results shall be recorded and kept on file for future verification by regulation agencies. In addition to the routine inspections, annual inspections appurtenances shall assess and mitigate, if necessary,performance of the detention ponds, and release structures. Criteria shall include accumulation of sediment and debris in the detention ponds, and release structures as well as any weather or vandalism related damage. Detention ponds shall be mowed on a regular basis during the growing season so as to remain free of vegetation that might impede their storage capacity. Stoneridge P.U.D. 10 Exhibit "A" City of Bozeman Storm Sewer Map Carroll Stream-Ditch O �• H to tn,o �, TRv2,1• - cc• � ° t I —`__.. p• m H r'�' �J' /JJ J 9 S °t�• i s V N't 2300Nj'-i,I 'Ili P P n P w Ir ~SU u I r . r• \_♦•\�♦.O..w.I I 9Sce-- �+� _ H5p+ �u wH. 2r - C 2200- - a-'•2.3003 1 70 ` is ♦♦ •.f. ♦♦ •P.c � '''� � _ , " ^ N - o e i ti to ♦\ N s, ♦ _ ---------------------r---___-._____„ _________ emu, s,.l N yi Iles, w -� \ P i `� N � .p \ 1 � � a I. •Pq � I - L - i. e. I .7 ♦♦ , Yl --a- 3li30• I---q "-------y- ••-----b �♦ -____.• ---- ----------- ------- ,- -•--~---'_` _ u H ___ -_ + 1 i S. 22nd '-- G'O, N. 22 nd AVE - 1 ♦ , _ :r____ ¢ x 2200 k, u - _ `♦ `��r1~ - © SID 330-._n.:•.rr1.�e-s t_ i a r Ts---- _ 1 la, y�� - __ _ �••. - - l• : _ �_� III • ..r v � _ O _-. _ __ '' 9�•,• U.. _; ``� � t'v I pqH I I u I e I � A I • ' D •~ .� I ' :• r y • N __ Z ^ • ````� y09 ' -- -------- OP N. 210 AVE.---------------�---"- I.4.2100 V, •� JC V P . 11 N - I + M M - P P + P N _ _.. `N IO O2000-- _ i S. 201A AVE. - 15 - ,..J.yS.�-D�. �. 56l — ---- a' P I I P I t4. Ht a C �y + to i '• >• " > s H w c R I < w r y_n - -__1--f We + t I r °' .' - -- - - - --- -- - - - N. 201A AVE u I O - I I + I I PLC! 3 �y v ----------------------» N wr LI -1 [ - - - -- - y -- -' - •-- ' i J.. tv I I pqq, I . 1 -a 2000 N 0� W _ - V O Y � _ � P •1 P � Y N _ w � I. _ _ .. • . - � I I w ( I I v l - I v I C s ► _I � � •' P I i t rn I K c i S U B 1 V 1900 '-Y�'-- 9 to A` a II II O� � a, }'Y•I SRC 'I 1 m C 1 i Fi RMERS CANAL t I - _Q�_-•190C !� t 1 I^ V N V V�1 4 I _ 1 1 T NI t 1 p (Q� t 1 --� y C 2 a N O O 0 v O O 1 1 a OO O O Scale: 1" =400' EXHIBIT "B" POND LOCATIONS LEGEND STONERIDGE P.U.D. SUBDIVISION Dgi SECTION CORNER O MONUMENT AS DESCRIBED • SET S/e'din.RCILAR W/ACW CA P P MHE®=MORR150N-IWERLE.INC' EXCEPT AT COUNTY ROAD WHERE p YELLOW PLA511C CMS ARE SET. G 1/4 CORNER FOUND AS DESCRIBED I 1/4 CORNER SET MONUMENT GRACE BREAK Im`•� ROAD GRADE ® SEWER HYDRANTS ® WELL IU. POWER POSE —.—..lcv u.�H I I I I --SE WQE MAW PA I- PUBLIC UTILITY EASEMENT 100 YEAR fL000F'WN DROP INLET 1 I 4.� PDNO OUTLET I 1 I I ........ MONTONNC YELL i I ....... it7 V NO ACCESS STRIP , i1 1 I I I I I fn I / ! i POND •10rz � � —POND @2 ti --- ------_ / r - I P I r`� 1 1 11- ' POND •�3 '/ _ PON "l �_J-- POND •4 ----51ONERDGE OR. POND v8 E i; OND ■gl POND •5 'Fr DR. PONDDR /I - i ---1 j t MAPLEWOOD SF. --�. ;I �A• DR. - +-�_--- _ ----•-�-_�----_—•__---•---------- N. 19TH AVENUE _— H. f9ff+AVENUE I I lil I I I I I I I11 I t I 1 I I III I I 1 E ' i i I1itl T I it MORRISOIN S�RE�Rs GRAPHIC SCALE C41 NIAIERLE NC. SINPLACE 1945 ' SINCE 1945 lm An Employcc-0—ud Company -- -- P O.th1 III! 901 96A a,,,,MT 59T11 c:'4onr.(kb)587-072, F-14CQ 5V7 1176 REV1510N DATE: IN m7) REV1510N DATE: I Inch- 200 fL DRAWN BY: GAIN DATE: 11/6/97 II•X17' scab: I inch - 200 FL 2'CanmuF Interval CHECKED BY: TVA DRAWING NO.:2605/011/EXHIBITp EXHIBIT •C.1' LEGEND DRAINAGE AND GRADING PROPOSED CONTOURSSTONERIDGE P.U.D. SUBDIVISION PLAN EXISTING CONTOURS PROPOSED PONDS I 1 coco _ _ I PL 22nd AVE \fij — — I I I \ \ `\ ..�\ I 1 / — I ~ I 1 I bf will— tv TMN —1 � N.20th-AVE. ` � �a .-� "����� ` .r��, I I I `� ��--- �� \ MAPL WdoD STR ET \\ %�, N .ate -� — I � t 04 GM.MAYs~I ------ --- - ------------ m ------� ----------------- ------ - --------------_ ---_ - N. 19th AVE. ' - - N. 19th AVE. l�IORRISON swE;15 a iERS MAIERLE,INc. S'tiCEpuv 1945 An Employe-Oumed Company GRAPHIC SCALE Vo.B.1113 lot le:lM,W M !!mW%111 5,ril •Rm (lot)Stl-Cnl roc Imo'587-1176 REVISION DATE: r w m REVISION DATE: No 1 DRA'AN 6Y: CMW DATE 11/24/97 IN I-ENT 1 2605/011/STORM/DRAINMS TR D'NG : 1 it I-h- too n CHECKED BY, TUH DRAWING NO.: 11'XIY - Scalench . 200 IT 2'Contour Interval -- EXHIBIT •C.2" LEGEND DRAINAGE AND GRADING --- PROPOSED CONTOURS STONERIDGE P.U.D. SUBDIVISION PLAN EXISTING CONTOURS . I PROPOSED PONDS / / I A I\ TSCHACHE LANE aaD .,'a Y - 3eNAC I s Iae 1 1 L /\ TOP 0= COMMON OPEN SPACE 1. JA 41 ram_ P lip e, J\ i� 1 Lu .r J OR j��7 l J �i — 11 1 1j DCT POND I � ` 1 ; i j riORlelttxrNDDO ; _ so' sol EE ^r, _ - I_ - ��;i WEST OAK STREET - --- _ -- --------WEST OAK STREET `- L ' — — — — r----L---- ---------- GRAPHIC SCALE r EfWNEu2S MORRISO SCIENTISTS PLAN MAIERLE,iNIC. SIN E'1'935 fro . MERS DI FM I An Nmploy--O,uned Cbmp-y l Inch-100 R ►O.Dw 1117 901 twti,rbpl Bka Botanot K 11':1.hme(1J5)587-0721 Fm:(ICSI 587-1176 11'X1Y Scola: I inch -200 R. REVISICN DATE: 2' Contour Interval REASIGN DATE: DRAWN BY. CMW DATE 11/6/97 2605/011/STORM/DRAINMASTR DWG CHECKED BY: TMH OR.AMNG NO.: JOB NCI 2605.011.010 0310 SHEET I OF 3 EXHIBIT "C.3' LEGEND DRAINAGE AND GRADING PROPOSED CONTOURS STONERIDGE P.U.D. SUBDIVISION PLAN �r ---- EXISTING CONTOURS kT. PROPOSED PONDS i- =--J BAXTER LANE 3 36 T. 1 S., R. 5 E. -------5 BAX7ER LAN \ — ---= —_ T. 2 S., R. 5 E. 81,750 V7 0CT I ma y W/15•RCP.$-ORTO Ix C,swot OVA0. Mn, ow I V It it f/ sy 1 It \ AAA 't It \ / I 46 TSCHACHE LANE r —'T36HAC"El -' Lo.►r. 1 L 1 axl.le t l TOP OF CULMEA7 ELEV-471LI0 GRAPHIC SC ; _ `� -' MORRISON SL:E!1'STS lll_ [ MAIERLE,iNlC. SINCE 13±s (01 Finn A,A`mployee-Ou.ne Company l loch- 1D0 ti P0.Bo.IIIJ 7011[Ym0 lend 0-Yf 59711•?Mnc(0)587-0721 fw:(4C6)Sd'-!!'S 11'XI7* Scale: 1 inch - 200 It. REVISION DATE: 2'Contour Interval N N A ' DRAMBY: 0AW DATE: 11/6/97 2605/011/STORM/DR AINMS TP DhC CHECKED BY: 7LIH DRAWING NO., JOB NO: 26C5-011-0100310 SHEET 1 OF 3 APPENDIX C. EXISTING AND PROPOSED CULVERT CALCULATIONS > M RRT N PROJECT: = MO+`�` SO ` BY: DATE MI NO. ■■I MMERLE,INC. CHK: DATE PAGE: OF ��.Q� ��%^�V"„ C/``"_���'� �/�,G•-� VON:--e7 `� }i 25' PROJECT: RMORRISON BY: DATE PROA NO.■ MERLE,INC. CHK: DATE PAGE: OF I 1 t-c, , FIGURES 233 u FIGURE 36 HEADWATER DEPTH FOR CONCRETE ARCH CULVERTS 'TICAL WITH INLET CONTROL 'ITROL 169 x 106 154 x 97 3,000 1) (6 2 (3) 138 x 88 (1) (2) (3) 6 _ ,000 4.0 EXAMPLE 4 122 x 78 Size: 44"x 27" 4.0 3.0 3.0 5_ 115 x 72 1,000 Q=30 cfs 3 3 - 800 HW, HW p 3.0 _3 102 x 62 600 00 D (feet) . = 2'0 2.0 rr 8 -2 0 2. , 2 88 x 54 40 (1)1.02 2.30 -1.5 30 (2)0.99 �. 1.5 cn 200 (3) 2.27 1.5 3 -1.5 w = N infe N �� Z - 73 x 45 0 w �1.0 1.0 1.0 -1.0 1.0 z 65 x 40 80 Z 1.0 9 -.9 .9 a 0 60 f�PMP� = 5 .9 .9 50 G 3 ; 8 =.8 .8. LL 8 x 36 40 w _.8 .8 .8• Q To use scale(2)or(3) p 7 -.7 .7 t j 51 x 31/v 30 draw a straight line L 7 .7 ; (n 20 Through known values Lv 7 ; 0 of size and discharge Q 6 ='6 .6 X to intersect scale(1). : 6 6- i Z 44 x 27 From point on scale(1) p!.6 10 proiect horizontally to w1 5 -.5 5 L< 8 solution on either scale = (2)or(3).N ,5 .5 36 x 22 6 T.5- 5 -,4 .4 .4 rn 4 HW/D ENTRANCE �Q .4 2 1.4 29 X 1$' (11 Square edge .4 (2) Groove end with I p headwall D �(3) Groove end f -__-Protecting D 22 x 13 cS8 X,3b v✓ V no-ECT: MMORRISON BY: DATE PROI NO. ■ MAIERLE,INC. CHK: DATE PAGE: OF c4 �z5 /O, Z cFs Quo 7Vw -- 1" 06 .. 3.z4 240 CONCRETE PIPE DESIGN MANUAL FIGURE 43 FIGURE 44 CULVERT CAPACITY GFS 15-INCH D AMETER t� PIPE f 20:T'r_�»* r'/:,L-i ._..«•.---r- tom._... I III ! 7.2 Manning's n=0.012Lw W - Projecting Inlet .r . 1.�: w i _ -Y---•._ Outlet Unsubmerged — 7_ _ - L�F LL 6 4 �. o LU LU 5.6 14 LL ILL -jam 12 ILL Lu Uj 10 t1/1 jF.Y. Wui .` T-r+•j—P_' — r1r'�: _ .___._.__ Tom.... 4; ILL Lu ILL 2.4 N ..J_� .'_..1 _—�_ wLL 6 Lc i = 1.6 — --t'f- -� -�- I a LL o 1 4 -- j-i?a: h w , U. - 0.8 oFv.44 0 1 �4 6 8 10 121T 14 = 0 CULVERT DISCHARGE 0 IN CUBIC FEET PER SECOND - 4 = - D. PROPOSED DET/RET POND CALCULATIONS 6p PROJECT: MRRTSO•= y'you`� �J BY. DATE PROD.NO. MMERLT` E,1NCi CHK: DA TE PAGE: OF A - f, c, 5 Tc, T ro 2.5 2 V Cfs G r- y. MODIFIED RATIONAL METHOD DETENTION POND VOLUME CALCULATIOR POND#6 Qp=CiA PRE-DEVELOPMENT STONERIDGE MINOR#1 PND N.of"C"DR i=a"(DURATION)^-(b) (CITY OF BOZEMAN) BASIN AREA PRE;^ ACRES STORM EVENT NTENSIT STORM i COEFF (YR) (IN/HR) a b SLOPE_ 2 0.97 0.36 0.6 5 1.50 0.52 0.64 LENGTH-- r FT 10 1.87 0.64 0.65 25 2.24 0.78 0.64 MANNINGS N= ! "-707 50 2.74 0.92 0.66 100 3.05 1.01 0.67 PRE-DEV TC= 1151 MIN 0.19 HR PRE-DEV C= 0,24, MANNINGS N N STORM A= 0-6� PAVEMENT 0.02 R= 0.65 POOR GRASS 0.3 AVE GRASS 0.4 STORM INTENSITY= 1.87 IN/HR PRE-DEV Qp= 0.74 CFS STONERIDGE MINOR#1 PND N.of"C"DR POND#6 POST-DEVELOPMENT. STORM DURATION= BASIN AREA PRE,p 1,65 ACRES SLOPE= 0.v%! LENGTH= 400.FT MANNINGS N N - MANNINGS N= 0 3' PAVEMENT o 02 POOR GRASS 0.3 POST-DEV TC= 11.51 MIN 0.19 HR AVE GRASS 04 POST-DEV C= 0.77 I STORM INTENSITY= 1.87 IN/HR 10 YR POST-DEV Qp= 2.16 CFS i/ DELTA DURATION= 1 MAX VOLUME MAX VOLUME AVERAGE VOL ` POND VOLUME CALCULATIONS: (CFT) (CFT) (CFT) 1169.34 669.66 919-50 Triangle Release Constant Release DURATION INTENSITY Op POND VOLUME POND VOLUME RETENTION VOL (MIN) (IN/HR) (CFS) (CFT) (CFT) (CFT) � j 10.93 1.94 2.244 967.41 63805 3469.56 11.93 1.83 2.fl' 990.79 '649.12 12.93 1.74 2.00 1011.74 657A9 13.93 1.65 1.91 1030.58 663.48 14.93 1.58 1.83 1047.54 667.35 ' 15.93 1.52 1.75 106282 669.35 ( + t!77 16.93 1.46 1.68 1076.61 669.65 ! j' 17.93 1,40 1.62 1089-04 668.41 18.93 1.35 1.56 1100.24 665.78 _I 19.93 1.31 1.51 1110.30 661.86 20.93 1.27 1.47 1119.33 656.76 Y 21.93 1,23 1.42 1127.41 650.57 22.93 1.20 1.38 1134,59 643.36 o U 23.93 1.16 1.34 1140.96 635.22 24:93 1.13 1.31 1146,56 626.20 677 25.93 1.10 1,28 1151 A4 616.35 26.93 1.08 12.1 1155,65 605.73 I 27.93 1.05 1.21 115923 594.39 28.93 1.03 1.19 116221 582.36 fj 29.93 1.01 1.16 116464 569,68 30.93 0.98 1.14 1166.53 556.39 ' 31.93 0.96 1.11 1167.93 542.52 32.93 0.95 1.09 1168A4 528.10 33.93 0.93 1.07 1169.31 513.15' 34.93 0.91 1.05 1169.34 497.70 35.93 0.89 1.03 1168.96 481.77 36.93 0-88 1.01 1168,20 465.36 37.93 0.86 1.00 1167.05 448.56 I 38.93 0.85 0-9B 1165,55 431.32 `\ 39.93 083 0.96 1163,71 413.68 40.93 082 0:95 1161.53 395.65 41.93 081 0.93 1159,04 377.26 42.93 080 0.92 1156,25 358.50 43.93 0.78 0.91 1153,16 339.41 44.93 077 0.89 1149.79 319.98 45.93 076 0.88 1146,15 300'23 46.93 075 0.87 1142.25 280.18 47.93 074 0.86 1138.10 259.82 48.93 073 0.84 1133.70 239.18 49.93 0,72 0.83 1129.07 218.27 50.93 071 0.82 1124,21 197.08 51.93 0.70 0.81 1119.13 175.63 52.93 0,69 0.80 1113.84 153.93 53.93 069 0.79 1108.34 131.98 54.93 0.68 0.78 1102.64 109.80 .. MRRT PROJECT: MRO `�`ISO `N BY DATE PROD.NO. ■ f CHK: DATE MMERLE INC PAGE: OF c -P�112jo \J r3 AGE. +~ PVC o S��� = 3 5 n►i� >: JIMOMSON PROJECT: I'Pe — \ 1 W () r `S 0,BY: L 6 DATE LI/C1 PROD.NO.MMERLE,INC. CHK: DATE PAGE: t OF 7 /✓d, Z /Lo( �✓C� Fl s c2 Co r r S�a S06 Na G30 ( Coo` w �) F rt� +R" cat jx?rJio�/ w C/ Ac.. CD/o Per v 0.73 I6. vv Q �k� O, �s o. 49 5 F1yV (N16, , 9 7Z -'f @ MODIFIED RATIONAL METHOD POND W Qp=CIA PRE-DEVELOPME.AT i=a'(DURATION)A-(b) (CITY OF BOZEMAN) BASIN AREA PRE= 233 ACRES STORM EVENT NTENSIT STORM I COEFF (YR) (IN/HR) A B: PRE-DEV TC= 21.00 MIN 0.35 HR 2 0.68 0.36 0:6 5 1.02 0,52: PRE-DEV C= 0.3 10 1.27 0.64 0:65' 25 1.53 0.78 0.64' STORM A= 0.64 50 1.84 0.92 0,68 B= 0.65 100 2.04 1.01 0667 STORM INTENSITY= 1.27 IN/HR PRE-DEV Qp= 0.89 CFS POST-DEVELOPMENT BASIN AREA PRE= 2.33 ACRES t� POST-DEV TC= 5 00 MIN 0.06 HR POST-DEV C= 0,77 STORM INTENSITY= 3.22 IN/HR 10 YR POST-DEV Qp= 5.77 CFS j,, DELTA DURATION= 1 MAX VOLUME MAX VOLUME AVERAGE VOL POND VOLUME CALCULATIONS: (CFT) (CFT) (CFT) 2418.09 1586.70 2002.39 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME RETENTION VOL (MIN) (IN/HR) (CFS) (CFT) (CFT) (CFT) 4.75 3.33 5.9T 1442.55 ' 1223,01 5296.18 5.75 2.94 5.27 1533.66 1292.77 6.75 2.65 4.75 1612.11 1349.57 7.75 2.42 4.34 1680.88 1396.43 8.75 2.24 4'01 1741,95 1435.39 9.75 2.09 3.74 1796.73 1467.89 10.75 1.96 3.51 1846.25 1494.97 11.75 1.85 3.31 1891.31 1517.45 12.75 1.75 3.14 1932.50 1535.96 13.75 1.67 2.99 1970.32 1550.99 14.75 1.59 2.86 2005.16 1562.95 15.75 1.53 2.74 2037.36 1572.17 16.75 1.47 2.63 2067.18 1578.94 17.75 1.41 2.53 2094.85 1583.48 18.75 1.36 2.45 2120.56 1586.01 19.75 1.32 2.36 2144.50 1586.70 20.75 1.28 2.29 2166.80 1585.69 21.75 1.24 2.22 2187.60 1583.12 22.75 1.20 2.16 220T00 1579.10 23.75 1.17 2.10 2225-10 1573.74 24.75 1.14 2.04 2242.00 1567.13 Q 25.75 1.11 1.99 2257.77 1559.35 26.75 1.08 1.94 2272,49 1550.47 27.75 1.06 1.90 2286,21 1540.57 28.75 1.03 1.85 2299.00 1529;69-- 29.75 1.01 1.81 231092 1517.90 30.75 0.99 1.77 2322.00 1505.25 31.75 0.97 1.74 2332.29 1491.77 32.75 0.95 1.70 2341.84 1477.52 33.75 0.93 1.67 2350.67 1462.53 34.75 0.91 1.64 2358.84 1446.83 35.75 0.90 1.61 2366.35 1430.47 36.75 0.88 1.58 2373.26 1413.47 37.75 0.86 1.55 2379,58 1395.85 38.75 0.85 1.53 2385.33 1377.65 39.75 0.84 1.50 2390.55 1358.89 40.75 0.82 1.48 2395.26 1339.58 41.75 0.81 1.45 2399.46 1319.77 42.75 0.80 1.43 2403.20 1299.45 43.75 0.79 1.41 2406.47 1278.66 44.75 0.77 1.39 2409.31 1257.41 45.75 0.76 1.37 2411.72 1235.72 46.75 0.75 1.35 2413.73 1213.60 47.75 0.74 1.33 2415.34 1191.06 48.75 0.73 1.31 2416.57 1168.13 49.75 0.72 1.30 2417.43 1144.81 50.75 0.71 1.28 2417.93 1121.12 51.75 0.70 1.26 2418.09 1097.07 52.75 0.70 1.25 2417.92 1072.67 53.75 0.69 1.23 2417.42 1047.94 5475 0.68 1.22 2416.61 1022.87 55.75 0.67 1.20 2415.50 997.49 56.75 0.66 1.19 2414.09 971.79 57.75 0.66 1.18 2412,40 945.80 a M PROJECT: = +•`O�`�`ISO`•N BY: DATE PROD.NO. ■■ RRTMAIERLE,INC. CHK: DATE PAGE: OF rid r,r LS �o MODIFIED RATIONAL METHOD DETENTION POND VOLUME CALCULATIOR POND#8 Qp=CiA PRE-DEVELOPMENT STONERIDGE MINOR#1 PND N.of"B"DR i=a"(DURATION)"-(b) (CITY OF BOZEMAN) BASIN AREA PRE`--r' ACRES STORM EVENT NTENSIT STORM I COEFF (YR) (IN/HR) a b SLOPE= 2 0.88 0.36 0.6 5 1.35 0.52 0.64 LENGTH= FT 10 1.69 0.64 0.65 25 2.03 0.78 0.64 I MANNINGS N= 50 2.47 0.92 0.66 100 2.75 1.01 0.67 PRE-DEV TC= 13.47 MIN 0.22 HR PRE-DEV C= =p7m MANNINGS N N STORM A PAVEMENT 0.02 9= POOR GRASS 0.3 AVE GRASS 0,4 STORM INTENSITY= 1.69 IN/HR PRE-DEV Qp= 1.38 CFS STONERIDGE MINOR#1 PND N.of"B"DR POND#8 POST-DEVELOPMENT STORM DURATION= BASIN AREA PRE 3.4 ACRES SLOPE= ir-1.035, LENGTH= FT MANNINGS N N MANNINGS N= PAVEMENT 0.02 POOR GRASS 0.3 POST-DEV TC= 13.47 MIN 0.22 HR AVE GRASS 0.4 POST-DEV C= STORM INTENSITY= 1.69 IN/HR 10 YR POST-DEV Qp= 4.02 CFS / DELTA DURATION= MAX VOLUME MAX VOLUME AVERAGE VOL POND VOLUME CALCULATIONS: (CFT) (CFT) (CFT) 2546.66 1457.84 2001.75 Triangle Releas Constant Release DURATION INTENSITY Qp POND VOLUM POND VOLUME RETENTION VOL (MIN) (IN/HR) (CFS) (CFT) (CFT) (CFT) 12.79 1.75 4.16 2106.05 1389.03 7025.76 13.79 1.66 3.96 2149:89 1410.02 14.79 1.59 3.78 2189.80 1426.62 15.79 1.52 3.63 2226.21 1439.29 16.79 1.46 3.49 2259.49 1448.44 17.79 1.41 3.36 2289.92 1454.40 18.79 1.36 3.24 2317.78 1457.45 19.79 1.32 3.13 2343.29 1457.84 20.79 1.27 3.03 2366,63 1455.78 21.79 1.24 2.94 2387.98 1451.46 22.79 1.20 2.86 2407.48 1445.05 23.79 1.17 2.78 2425.28 1436.69 24.79 1.14 2.71 2441.47 1426.51 25.79 1.11 2.64 2456.18 1414.63 26.79 1.08 2.57 2469.49 1401.16 27.79 1.06 2.51 2481.49 1386.18 28.79 1.03 2.45 2492,26 1369.79 29.79 1.01 2.40 2501.86 1352.07 30.79 0.99 2.35 2510.38 1333.08 31.79 0.97 2.30 2517.82 1312.89 32.79 0.95 2.26 2524.29 1291.56 33.79 0.93 2.21 2529.82 1269.15 34.79 0.91 2.17 2534.46 1245.70 35.79 0.90 2.13 2538.24 1221.27 36.79 0.88 2.09 2541.22 1195.90 37.79 0.86 2.06 2543.41 1169.63 38.79 0.85 2.02 2544.87 1142.50 39.79 0.84 1.99 2545.61 1114.54 40.79 0.82 1.96 2545.66 1085.79 41.79 0.81 1.93 2545.07 1056.27 42.79 0.80 1.90 2543,84 1026.02 43.79 0.79 1.87 2542.01 995.07 44.79 0.77 1.84 2539.60 963.44 45.79 0.76 1.82 2536.62 931.14 46.79 0.75 1,79 2533.10 898.22 47.79 0.74 1.77 2529.06 864.68 48.79 0.73 1.74 2524.52 830.56 49.79 0.72 1.72 2519.49 795.86 50.79 0.71 1.70 2513.99 760.61 51.79 0.70 1.68 2608.03 724.62 52,79 0.70 1.66 2501.63 688.51 53.79 0.69 1.64 2494.80 651.70 54.79 0.68 1.62 2487.55 614.40 55.79 0.67 1.60 2479.91 576.62 56.79 0.66 1.58 2471,87 538.39 57.79 0.66 1.56 2463.45 499.70 58.79 0.65 1.54 2464.67 460.58 59.79 0.64 1.53 2445.53 421.04 60.79 0.63 1.51 2436.03 381.08 61.79 0.63 1.49 2426.20' 340.73 62.79 0.62 1.48 2416.04 299.98 63.79 0.61 1.46 2405.56 258.84 64.79 0.61 1.45 2394.76 217.34 65.79 0.60 1.43 2383.66 175.47 66.79 0.60 1.42 2372.26 133.25 67.79 0.59 1.41 2360.57 90.69 68.79 0.59 1.39 2348.60 47.79 69.79 0.58 1.38 2336,35 4.55 70.79 0.57 1.37 2323.83 -39.00 71.79 0.57 1.36 2311.05 -82.87 72.79 0.56 1.34 2298.01 -127.05 73.79 0.56 1.33 2284.72 -171.53 74.79 0.55 1.32 2271.18 -216.30 75.79 0.55 1.31 2257.40 -261.36 76.79 0.55 1.30 2243.38 -306.70 77.79 0.54 1 29 2229.14 -352.32 ` PROJECT: f•/ EIMOFKSON BY: DATE PROJ.NO. T■mMMERLE,INC HK: DATE PAGE: OF C �J--� <� to 43q 5S c r-5 MODIFIED RATIONAL METHOD DETENTION POND VOLUME CALCULATIOR POND#9 Qp=CiA PRE-DEVELOPMENT STONERIDGE MINOR#1 PND S.of"B"DR i=a'(DURATION)A-(b) (CITY OF BOZEMAN) BASIN AREA PRE s ACRES STORM EVENT NTENSIT STORM i COEFF (YR) (IN/HR) a b SLOPE= 2 1.02 0.36 0.6 5 1.58 0.52 0.64 LENGTH= FT 10 1.98 0.64 0.65 25 2.37 0.78 0.64 MANNINGS N= 50 2.90 0.92 0.66 100 3.23 1.01 0.67 PRE-DEV TC= 10.56 MIN 0.18 HR PRE-DEV C= MANNINGS N STORM `PAVEMENT 002 `POOR GRASS 0.3 AVE GRASS O.A. STORM INTENSITY= 1.98 IN/HR PRE-DEV Op= 0.67 CFS STONERIDGE MINOR#1 PND S.of"B"DR POST-DEVELOPMENT STORM DURATION= BASIN AREA PRE ' 12 ACRE-S SLOPE LENGTH= __ 400 FT MANNINGS N N MANNINGS N= =0 PAVEMENT 0.02 POOP.GRASS 0.3 POST-DEV TC= 10,56 MIN 0.18 HR AVE GRASS 0.4 POST-DEV C= 071, STORM INTENSITY= 1.98 IN/HR 10 YR POST-DEV Op= 1.66 CFS DELTA DURATION= MAX VOLUME MAX VOLUME AVERAGE VOL POND VOLUME CALCULATIONS: (CFT) (CFT) (CFT) 825.13 472.55 648.84 Triangle Releas Constant Release DURATION INTENSITY Qp POND VOLUM POND VOLUME RETENTION VOL (MIN) (IN/HR) (CFS) (CFT) (CFT) (CFT) 10.03 2.05 1.72 682.64 450.23 2479.68 11.03 1.92 1.62 700,53 458.65 12.03 1.82 1.53 716.42 464.83 13.03 1.73 1.45 730.57 469.05 14.03 1.65 1.38 743,19 471.56 15.03 1.57 1.32 754.47 472.55 16.03 1.51 1.27 764.55 472.18 17.03 1.45 1.22 773.54 470.59 18.03 1.40 1.17 781.56 467.89 19.03 1.35 1.13 788.69 464.17 20.03 1.31 1.10 795.00 459.52 21.03 1.27 1.06 800.57 454.02 22.03 1.23 1.03 805.44 447.73 23.03 1.19 1.00 809.67 440.71 24.03 1.16 0.97 813,32 433.01 25.03 1.13 0.95 816.40 424.66 26.03 1.10 0.93 818.97 415.72 27.03 1.07 0.90 821.05 406.22 28.03 1.05 0.88 822.68 396.20 29.03 1.03 0.86 823.88 385.67 30.03 1.00 0.84 824.67 374.68 31.03 0.98 0.83 825.08 363.24 32.03 0.96 0.81 825.13 351.38 33.03 0.94 0.79 824.83 339.12 34.03 0.93 0.78 824.20 326.47 35.03 0.91 0.76 823,27 313.46 36.03 0.89 0.75 822.03 300.11 37.03 0.88 0.74 320.51 286.42 38.03 0.86 0.72 81872 272.42 39.03 0.85 0.71 816.67 258.11 40.03 0.83 0.70 814.37 243.51 41.03 0.82 0.69 811.04 228.63 42.03 0.81 0.68 80907 213.47 43.03 0.79 0.67 806.08 198.06 44.03 0.78 0.66 802.88 182.40 45.03 0.77 0.65 799.48 166.50 46.03 0.76 0.64 795.88 150.37 47.03 0.75 0.63 792.10 134.01 48.03 0.74 0.62 788.13 117.44 49.03 0.73 0,61 783.98 100.66 50.03 0.72 0.60 779.66 83.67 51.03 0.71 0.60 775.18 66.49 52.03 0.70 0.59 770.54 49.12 53.03 0.69 0.58 765.74 31.57 54.03 0.69 0.58 760.79 13.83 55.03 0.68 0.57 755.70 -4.08 56.03 0:67 0.56 750.47 -22.15 57.03 0.66 0.56 745.10 -40.39 58.03 0.65 0.55 739.59 -58.79 59.03 0.65 0.54 733,96 -77.34 "k, �T PROJECT: = MORRISON BY: DATE PROJ.NO. ■■I MERLE,INC. CHK. DATE PAGE: OF �.�� , �C��N GI A re.� � 8• �( �c�s Gr �G ✓r no� cvk-( ,� = � /�/.�� p �s 2 fErs A --val 20 COO a7 C G �r rP f //r� l GNU = •v."HJ 2 G 2 116j� ?ov P(� ) 5'tc, 44�10 � V� j X Qp=CiA PRE-DEVELOPMENT i=a'(DURATION)^-(b) (CITY OF BOZEMAN) BASIN AREA PRE_'> 8,4 ACRES STORM EVENT NTENSIT STORM i COEFF (YR) (INIHR) A B PRE-DEV TC= 28i00 MIN 0.47 HR 2 0.57 0.36 0.6 5 0.85 0.52 0.64 PRE-DEV C= 10 1.05 0.64 0.65 25 1.27 0.78 0.64 STORM A= b,64 50 1.52 0.92 0.66 B= 0.65 100 1.68 1.01 0.67 STORM INTENSITY= 1.05 IN/HR PRE-DEV Op= 2.65 CFS POST•DEVELOPMENT BASIN AREA PRE_'?' 8.4 ACRES POST-DEV TC= 28.00 MIN 0.47 HR POST-DEV C= 0.3 STORM INTENSITY= 1,05 INIHR 10 YR POST-DEV Qp= 2.65 CFS DELTA DURATION= MAX VOLUME MAX VOLUME AVERAGE VOL POND VOLUME CALCULATIONS: (CFT) (CFT) (CFT) 32.05 -021 15.92 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME RETENTION VOL (MIN) (IN/HR) (CFS) (CFT) (CFT) (CFT) 26.60 1.09 2.74 32.05 -2.59 7439.04 27.60 1.06 2.67 9A2 -0.21 28.60 1.04 2.61 -14.52 -0.46 29.60 1.01 2.55 -39.72 -3.21 30.60 0.99 2.50 -66.09 -8.34 31.60 0.97 2.45 -93.57 -15.73 32:60 0.95 2.40 -122.12 -25.27 33.60 0.93 2.35 -151.66 -36.86 34.60 0.92 2.31 -182.17 -50.43 35.60 0.90 2.26 -213.58 -65.87 36.60 0.88 2.22 -245.86 -83.11 37.60 0.87 2.19 -278.97 -102.08 38.60 0.85 2.15 -312.88 -122.71 39.60 0.84 2.11 -347,54 -144.94 40.60 0.82 2.08 -382.94 -168.71 41.60 0.81 2:05 -419.03 -193.95 42.60 0.80 2.01 -455.79 -220.62 43.60 0.79 1.98 -493.20 -248.68 44.60 0.78 1.96 -531.24 -278.06 45.60 0.76 1.93 -569.87 -308.73 46.60 0.75 1.90 -609.07 -340.64 47.60 0.74 1.87 -648.84 -373.76 48.60 0.73 1.85 -689.14 -408.05 49.60 0.72 1.83 -729.96 -443.47 50.60 0.71 1.80 -771.28 -479.99 51.60 0.71 1.78 -613.09 -517.58 52.60. 0.70 1.76 -855.37 -556.20 63.60 0.69 1.74 -898.11 -595.83 54.60 0:68 1.71 -941.29 -636.44 55.60 0.67 1.69 -984.90 -678.00 56.60 0.66 1.68 -1028.92 -720.49 57.60 0.66 1.66 -1073.35 -763.88 58.60 0.65 1.64 -1118.17 -808.15 59.60 0.64 1.62 -1163.37 -853.28 60.60 0.64 1.60 -1208.94 -899.25 61.60 0.63 1.59 -1254.87 -946.03 62.60 0.62 1.57 -1301.16 -993.61 63.60 0.62 1.55 -1347.78 -1041.96 64.60 0.61 1.54 -1394.74 -1091.08 65.60 0.60 1.52 -1442.03 -1140.93 66.60 0.60 1.51 -1489,63 -1191.52 67.60 0.59 1.49 -1537.54 -1242.81 68.60 0.59 1.48 -1585.75 -1294.80 69.60 0.58 1.46 -1634,26 -1347.46 70.60 0.58 1.45 -1683.05 -1400.79 NMRRT N PROJECT: j OP,/ r '(-l �iNO/ =/f JSO y' O "" `` BY: /V j�� DATE 9 �7 l��I PROJ.NO. `LG dQ7 MMERLE INC. f CHK: DATE PAGE: , OF � �-F- �1vialp�1� 4 _ Gil �,j _ = Z,C) ✓ Ccc,�e i61 �) awe I,C7 YZ 6 j Lc7w?s7 D� �rt �� /o�/��t — .So r-%,�► �,� c,� ��,f�� /�J�, 7��. ceu .ud AGO �r /is �hi�a�clt/ �d^ ��d / T_ rlr��ro� �/ U 6 V,4 - 20�O C4 Lk s 0 Li vj (�6 _ y s I j ti=0 �l1 �> A J Q= o,s �15 ��„�•I,�IS ,��I .�, �� Q�� ��T PROJECT: = MORRISON BY: DATE PROD.NO. ■ i MMERLE INC, f CHK: DATE PAGE: Z OF z 2oo'j-D g Orr c-c, w ;�. 0.0ti CWn1N0-1 �Da-- PaoJEcr. 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